There are elevator installations, so-termed ‘multi-mobile elevators’, such as disclosed in, for example, EP-A1-1 489 033, with elevator car arranged one above the other in a shaft. Elevator installations comprise at least two elevator cars arranged one above the other and movable vertically on guide rails, wherein each is equipped with a separate drive and a separate counterweight. The floors to be served are in this regard preferably distributed in such a manner that an upper elevator car travels to the upper floors and a lower elevator car travels to the lower floors. However, intersections of this allocation are also realized.
At the same time, however, it is in general endeavored to achieve a high level of efficiency or rate of passenger and/or goods transport in the concept or construction of elevator installations. A significant factor in that respect is optimum utilization of the cross-section of the elevator shaft.
This in turn is effected, inter alia, by a counterweight design which is as slender and space-saving as possible, so that the elevator car can be of the largest area possible in the cross-section thereof.
In the case of a duo-mobile or multi-mobile elevator installation such as is known from the state of the art an optimization of the size of the counterweight is even more stringent, because the elevator shafts of such elevator installations by contrast to conventional elevator installations with only one elevator car have to accommodate not just one counterweight, but two or more counterweights.